/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * Copyright 2009 Sun Microsystems, Inc.
 */

package org.forgerock.opendj.ldap.requests;

import java.util.List;

import org.forgerock.opendj.ldap.ByteString;
import org.forgerock.opendj.ldap.DecodeException;
import org.forgerock.opendj.ldap.DecodeOptions;
import org.forgerock.opendj.ldap.controls.Control;
import org.forgerock.opendj.ldap.controls.ControlDecoder;
import org.forgerock.opendj.ldap.responses.ExtendedResult;
import org.forgerock.opendj.ldap.responses.ExtendedResultDecoder;

/**
 * The Extended operation allows additional operations to be defined for
 * services not already available in the protocol; for example, to implement an
 * operation which installs transport layer security (see
 * {@link StartTLSExtendedRequest}).
 * <p>
 * To determine whether a directory server supports a given extension, read the
 * list of supported extensions from the root DSE to get a collection of
 * extension OIDs, and then check for a match. For example:
 *
 * <pre>
 * Connection connection = ...;
 * Collection&lt;String&gt; supported =
 *     RootDSE.readRootDSE(connection).getSupportedExtendedOperations();
 *
 * ExtendedRequest extension = ...;
 * String OID = extension.getOID();
 * if (supported != null && !supported.isEmpty() && supported.contains(OID)) {
 *     // The extension is supported. Use it here...
 * }
 * </pre>
 *
 * @param <S>
 *            The type of result.
 */
public interface ExtendedRequest<S extends ExtendedResult> extends Request {

    @Override
    ExtendedRequest<S> addControl(Control control);

    @Override
    <C extends Control> C getControl(ControlDecoder<C> decoder, DecodeOptions options)
            throws DecodeException;

    @Override
    List<Control> getControls();

    /**
     * Returns the numeric OID associated with this extended request.
     *
     * @return The numeric OID associated with this extended request.
     */
    String getOID();

    /**
     * Returns a decoder which can be used to decoded responses to this extended
     * request.
     *
     * @return A decoder which can be used to decoded responses to this extended
     *         request.
     */
    ExtendedResultDecoder<S> getResultDecoder();

    /**
     * Returns the value, if any, associated with this extended request. Its
     * format is defined by the specification of this extended request.
     *
     * @return The value associated with this extended request, or {@code null}
     *         if there is no value.
     */
    ByteString getValue();

    /**
     * Returns {@code true} if this extended request has a value. In some
     * circumstances it may be useful to determine if a extended request has a
     * value, without actually calculating the value and incurring any
     * performance costs.
     *
     * @return {@code true} if this extended request has a value, or
     *         {@code false} if there is no value.
     */
    boolean hasValue();

}
